36hp cam bearings. Machining the case for bearings.

[Victor Frisbee]

I am assembling the necessary parts and core motors to build my first 36hp engine. (I've rebuilt many 1600s) I even found a engine case in the correct serial # range for my bug.

I knew that I could have the mains line bored if necessary. I had also researched on the internet that although the 36hp case does not have cam bearing, RIMCO could machine the case to accept bearings. (40hp I assume?)

Well... I just got off the phone with RIMCO and they DO NOT machine 25 or 36hp cases for cam bearing! Now what!?

Can this be done? By who? How much $$$ What is involved? Is a special camshaft required?

Please advise as this could be a major bump in the road for my planned engine.

JD 8^)
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[Unkl Ian]

Compare the diameter of the bearing journals on the 36 and 40 hp motors.

[Sunroof53]

Mr okrasa on here does the work.You do not need a special cam ,I do know that the bearing journal is the same size but not sure what bearings he uses.

[Mr. Okrasa]

[Sunroof53]

Sorry i have read somewhere that it was being done and mistakenly thought it was you .

[beetleseb]

I'm sure I've seen it done before.

Now if only I can remember where.......

Seb

[Mr. Okrasa]

[beetleseb]

Is it just me or does it look like there are cam bearings in this block?

http://www.thesamba.com/vw/forum/viewtopic.php?t=344193

Hard to tell but.............

Seb

[Mr. Okrasa]

[ProjectX]

I too have talked to RIMCO about adding cam bearings to a 36HP block, and as Mr. Okrasa points out, can't do it.

However, how about plating the cam itself and oversizing it to the dimensions of the block?
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Even my nuts are plated.....

195? Project "X"
1954 Oval Convertible

[beetleseb]

After reading the above, if the block needs it I think I'd just bin the block. My machinist in the UK is a motorbike man and reckons he can do it, but I'm no going to take the chance.

If it was an ali 25hp block you could weld the holes up and remachine but its a lot of hastle!

Seb

[Mango Juice]

I have heard recently it has been done

I have not seen it nor have I seen the engine run.

A few people here know of the Hot Rodder.

I'm very excited to see this beast run! and how long it will last!

I was also told by Todd at RIMCO it cannot be done.

[jcannon]

I know I've seen 36ers could be bored for cam inserts, and am sure I had it done 30 years ago. So I looked.....

According to "How to Hotrod Volkswagen Engines" by Bill Fisher, 1970, on page 117 It says "Should your case be an older 36 HP or 40 HP unit, RIMCO can install insert-type cam bearings to ensure you'll have good oil pressure after your rebuild". It goes on to say the cost for align boring a 36er or 40 and installing insert-type cam bearings (including inserts) is $55. Align bore alone is $29.

That is pretty specific information. Are we sure they didn't do it at one time, and the process has been forgotten? Maybe the tooling is laying on a shelf somewhere.

The book could be wrong. But this is why some of us think it can be done.

[TomSimon]

I was talking with a friend about this, who wants to salvage a rear early Porsche case, and it got me thinking about how I could salvage a 36hp case whos cam tunnel is .003" out of round. I determined, for my purposes, I'd be better off buying 3 cases to find one good one.

A guy could have a 36hp cam with 0.25mm oversized bearing journals made for him, then cut the cam tunnel in the case to 0.25mm oversize cam bore.

But it come down to economics... Unfortunately the 36hp/356 Porsche onlycam boring tooling won't be cheap, neither will the one-off special cam. If such a boring tool already exists for the 36hp/356 Porsche, which is different diameter and different saddle spacing than a type 1, then it might be worth saving a rare engine case.

Some background:

Hard chroming to build up worn and ground undersize crankshaft bearing journals and was once very common. Not so much anymore, as it's a very precise process that takes a large investment and environmentally monitoring (read: $$$$) Unfortunately, VW cams are cast iron. I am not certain, but I don't think you can hard chrome cast iron or a cast iron vw or Porsche cam. I have only used that process on forged and billet crankshafts.

I have had billet cams made for T1's, those are $300 per blank when they make 10 at a time, and another $400 to have 1 cam heat treated, ground, heat treated, then final ground. Double that if you'd like a single one made to fit a 36hp... but you could make it with oversize bearing surfaces.

I have also had cast iron VW cams with undersize cam lobes ground further undersize, built up with 'hard weld', then had the lobes reground with a new longer duration higher lift profile. Babe Erson once did this for me, so did Dema Elgin. Web cam might offere this, maybe Steve Long. When I did it, it cost about $300/cam, but I have never had the journals built up, so add another $100 I'm guessing?

So what I see is this:
Have a cast iron cam hard welded up, lobes ground to whatever profile he wanted and 0.25mm oversized bearing journal diameters. Then have Rocky Jennings build you a 36hp/356 Porsche cam boring bar set up. Then a guy could offer cam tunnel machining services to the rest of us 36hp nuts!
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[grueni]

is there really a need of cam bearings? there are couple of porsche 356 engines that in racetrim see over 8000RPM.
and those engines have so heavy valves and push rods that they allways need way much more spring pressure than a 36er.

[Sunroof53]

I was reading a 58 workshop manual the other day and you can do it by machining the case halfs ,then rebore evrything back to stock size.it even gives limits ofhow much you can take from each half.lots of machining but it can be done.

[hazetguy]

[Sunroof53]

I will scan the pages for you. Its a Vw workhop manual that was for main agents .There are quite a few on the samba that have been scanned ,but you would have to search.I will do it later tonight .It shows a very primitive tool for machining the case halfs but now you would use a mill and face tool.

[Sunroof53]

Here you go:

[hazetguy]

thanks for posting that information.